When selecting a proportional font (like Adobe Times) for gnome terminal, _lots_ of extra white space shows up.
The only way proportional fonts make sense is to add padding to each character to emulate a fixed width font; this is what xterm does. I'll send the bug upstream, but even if it's fixed I'm not going to put the patch in Winston because it will almost certainly require significant code changes and potentially introduce instability.
Upstream as http://bugzilla.gnome.org/show_bug.cgi?id=57442 Closing in RH bugzilla